Apparatus for forming sheet-metal fin-strips for heat-exchangers

ABSTRACT

Apparatus for the automatic transformation of thin metal-stock into fin-strips of predetermined widths and lengths with groups of associated apertures and protuberances, for use in structuring core-units for heat exchangers required for controlling temperature conditions in various kinds of enclosures. The apparatus has juxtaposed elements, including one element for forming tube-embracing apertures and intermediate protuberances in the metal-stock and another element for recurring cut-off of predetermined lengths of finished fin-strips. All elements are arranged in series with antecedent elements for hemming the metal-stock, controlling the feeding and linear travel thereof, and with subsequent series of elements for advancing, discharging and stacking the finished fin-strips subject to later use in the structuring of desired types of heat-exchanger core-units. All of the elements are powered by a series of motors under the control of a manually and automatically operated switch mechanism.

United States Patent Young et al.

[ 1 Mai-.21, 1972 [54] APPARATUS FOR FORMING SHEET- METAL FIN-STRIPS FORHEAT- EXCHANGERS [72] inventors: Fred M. Young; William V. Astrup;

Ronald E. Jones, all of Racine, Wis.

[73] Assignee: Young Radiator Company, Racine, Wis.

[22] Filed: May 12, 1969 [21] Appl. No.: 823,925

[52] U.S.Cl. ..113/1C,83/337 [51] Int. Cl ..B2ld 53/02 [58] FieldofSearch ..113/1, 118;29/202, 157.3;

[56] References Cited UNITED STATES PATENTS 195,824 10/1877 Jaeger..83/349 687,905 12/1901 Seymour ..113/1 1,379,005 5/1921 Eligh....113/1 1,484,600 2/1924 Witte ....113/1 1,640,147 8/1927 Fedders eta1. ....113/1 1,742,414 1/1930 Rogers ..29/202 2,083,370 6/1937 Greulich..83/337 2,753,001 7/1956 Page ..83/337 3,482,299 12/1969 Davidson eta1, ..113/1 2,876,723 3/1959 Lawrence ..113/1C FOREIGN PATENTS ORAPPLlCATlONS 266,913 3/1927 Great Britain ..113/1 PrimaryExaminer-Richard J. l-lerbst Attorney-Edwin Phelps and Arthur J.Hansonann [57] ABSTRACT Apparatus for the automatic transformation ofthin metalstock into fin-strips of predetermined widths and lengths withgroups of associated apertures and protuberances, for use in structuringcore-units for heat exchangers required for controlling temperatureconditions in various kinds of enclosures. The apparatus has juxtaposedelements, including one element for forming tube-embracing apertures andintermediate protuberances in the metal-stock and another element forrecurring cut-off of predetermined lengths of finished finstrips. Allelements are arranged in series with antecedent elements for hemming themetal-stock, controlling the feeding and linear travel thereof, and withsubsequent series of elements for advancing, discharging and stackingthe finished finstrips subject to later use in the structuring ofdesired types of heat-exchanger core-units. All of the elements arepowered by a series of motors under the control of a manually andautomatically operated switch mechanism.

17 Claims, 41 Drawing Figures FIN-STRIP DISCHARGING ELEMENT I FIN-STRIPADVANCING ELEMENT FIN STRIP-RECEVING coNvEYon' FlN-S R|P CUT OFF ELEMENTAPERTUREFROTUBERANT FORMING ELEMENT K-CIRCUIT CONTROL ELEMENT LINEARTRAVEL CONTROL ELEMENT 94 D-METAL s'rocx resume ELEMENT c-METAL STOCKHEMMING ELEMENT FE PAIENTEDMARZI I972 3,650,233

sum OlOF 11 8 con. SUPPORT ELEMENT D-METAL STOCK FEEDING ELEMENT C-METALSTOCK HEMMING ELEMENT LINEAR TRAVEL CONTROL ELEMENT K -OIRCUIT CONTROLELEMENT FIN-STRIP ADVANCING ELEMENT /FIN-S RIP CUT OFF ELEMENT-APERTURE'PROTUBERANT FORMING ELEMENT [NV/5m HRS. FRED M. YOUNG WILLIAMV. ASTRUP ONALD J NES ATTY FIN "STRIP DISCHARGING ELEMEN PATENTEDMAR 21I972 SHEET CEUF 11 INVl l /"l 0R5: FRED M. YOUNG WILLIAM V ASTRUP ONALDE. JONES ATTY PATENTEDMARZI I972 3,650,283

SHEET O3UF 11 m [N Vii/\l'l was; FRED M. YOUNG WILLIAM \l. ASTRUP R ALDE. J S BY:

ATT'Y PATENTEDMARZI .972 8,650,233

SHEET UQUF 1') m FIG. 13 46 QUINN!! INVENIORS FRED M. YOUNG WILLIAM V.ASTRUP NALD E. JONES ATT'Y FIG. I5

PAIENTEDIIARZI I972 3,650,233

sum 05 0F 11 INVENTORS: FRED M, YOUNG WILLIAM V. ASTRUP RALD E. JE

PATENTEDHAR21 1972 3,650,233

SHEET 0E 0F 1? FIGI? INVENTORS:

FRED M. YOUNG WILLIAM ASTRUP RONALD E. JONES ATT'Y PATENTEDMAR21 I972SHEET 07 0F 11 IN VENTORS: FRED M. YOUNG WILLIAM V. ASTRUP RONALD E.JONES ATT'Y PATENTEDMARZ] I972 3,650,233

SHEET 08 0F 11 INVI-JNIYIRSI FRED, M. YOUNG WILLIAM V. ASTRUP NALD E.JONES BY:

ATT'Y 5 H H] u E I?) H E "E I I- w z i :3 I; .qi: 31h F {13E 1.1 L Id:IL

u o o E: n u LO ll INVIi/JIHRS: g] FRED M. YOUNG I WILLIAM AS RU ERONALD E. JONES ATT'Y PATENTEDMAR 21 I972 SHEET IDUF 1% lNVliN'lU/(SjFRED M. YOUNG WILLIAM V ASTRUP PATENTEUHARZI i912 3,650,233

SHEET 11UF 11 AIR LUTCH FEED FIG. 32 ROLLER 0 FORM ROLLERS 2| HIGH LIMITSWITCH 1 FRED IVI. YOUNG WILLIAM V. ASTRUP R ALD E. JONES ATT'YAPPARATUS FOR FORMING SHEET-METAL FIN-STRIPS FOR l-IEAT-EXClI-IANGERSThis invention relates to an apparatus for the facilitatedtransformation of thin metal-stock into preformed, planar finstripsadapted for use in stacked arrangement on batteries of tubes to producecore-units for various types of heat exchangers.

The current-day economy constantly demands production facilities tomaterially reduce manufacturing and use costs. Such obtains in theindustry producing any type of heat exchanger involving stacks ofthin-metal, parallel-disposed, apertured fin-strips embracing a batteryof tubes, connecting opposed tanks, through which flows a fluid subjectto temperature change.

The main objects of this invention are: to provide an improved apparatusfor the high-speed production of aperturedprotuberant fin-strips ofpredetermined width and length from thin-metal stock; to provide anapparatus of this kind wherein thin-gage, metal-stock is drawn from acoil through a succession of metal-forming elements effecting thehemming of one or both of the lateral perimeters of the metal-stock andthe formation of a predetermined succession of associated apertures andprotuberances, and severed into predetermined, uniform lengths offin-strips finally transferred onto a platform; to provide an apparatusof this kind for maintaining a constant uniform linear travel of themetal-stock through the succession of fin-strip forming-elements to thepoint of discharging the finished fin-strips onto a conveyor foradvancing them to a position to permit the ordered removal thereof forlater use in structuring heat exchangers; to provide an apparatus ofthis kind capable of use with varying widths and thickness ofmetal-stock; to provide a series of accessories for manually and/orautomatically controlling the operation of the apparatus; and to providean apparatus of this kind of such practical design and arrangement ofthe elements as to make the production of fin-strips reasonably facileand economical and highly practical and gratifying in use.

In the adaptation shown in the accompanying drawings:

FIG. I is a perspective view of the entire apparatus clearly indicatingthe frame-supported sequence of the several essential elements thereof;

FIG. 2 is an end view of the fin-receiving conveyor;

FIG. 3 is a perspective view of a section of a preferred form offin-strip produced on the apparatus shown in FIG. 1;

FIG. 4 is a perspective view of a section of a fin-strip havingdifferent protuberant form from that of FIG. 3, and being possible ofproduction on an apparatus of this kind requiring only a different setof dies;

FIG. 5 is a perspective view of a section of a heat-exchanger core-unitformed with a stack of fin-strips of the type herein illustrated andexplained;

FIG. 6 is a top plan of the apparatus shown in FIG. 1, with themetal-stock omitted;

FIG. 7 is a front side elevation of the apparatus as shown in FIG. 6with the lead end of the metal-stock inserted into a hemmer element;

FIG. 8 is a front side elevation of the metal-stock hemming and feedingelements taken on the plane of 8-8 FIG. 8;

FIG. 9 is a left-face view taken on the plane of the line 9-9 of FIG. 8;

FIG. 10 is a top plan view of FIG. 9;

FIG. 11 is an enlarged, vertical, cross-sectional view taken on theplane ofthe line 11-11 ofFIG. 8;

FIG. 12 is a front side elevation of the aperture-protuberant formingelement and the fin-strip cutoff element viewed from the plane of theline 12-12 of FIG. 6, with the housing omitted;

FIG. 13 is a left-face view shown in FIG. 12, taken on the plane of theline 13-13 ofFIG. 12;

FIG. 14 is a top plan ofwhat is shown in FIG. 12;

FIG. 14A is a diagrammatic perspective of the gear-pulley train thatcontrols the functions of the intrinsic, core-elements that convertmetal-stock into fin-strips;

FIG. 15 is a much-enlarged, cross-sectional view taken on the planeofthe line 15-15 ofFlG. 12;

FIG. 16 is an enlarged, transverse, crossasectional view taken on theplane of the line 16- 16 of FIG. 15;

FIG. 16A is a perspective view of one of the punch-activating lobes thatform apertures in the metal-stock;

FIG. 17 is a further enlarged, cross-sectional view taken on the planeof the line 17-17 of FIG. 16;

FIG. 18 is a much-enlarged, partial face view of the upper fin-stripforming cylinder taken on the plane of the line 18- 18 of FIG. 16;

FIG. 19 is a similar view of the lower fin-strip formingcylinder asviewed from the plane of the line 19-19 of FIG. 16;

FIG. 19A is an enlarged, cross-sectional view of the punchactivatinglobe as shown in FIG. 16;

FIG. 20 is an enlarged end elevation of the fin-strip cutoff element.

FIG. 21 is a cross-sectional view of the fin-strip cutoff element takenon the plane of the line 21-21 of FIG. 20;

FIG. 22 is a top plan view of what is shown in FIG. 20 taken on theplane of the line 2222;

FIG. 23 is a partial vertical, sectional view taken on the plane of theline 23-23 of FIG. 20;

FIG. 24 is a top plan of the finished tin-strip advancing-element anddischarge element as viewed from the plane of the line 24-24 of FIG. 7;

FIG. 25 is a cross-sectional view taken on the plane of the line 25-25of FIG. 24;

FIG. 26 is a vertical, sectional view of what is shown in FIG. 24 takenon a transverse plane of FIG. 24;

FIG. 27 is a perspective view of the well-known Disc-O- Torque type ofair-clutch;

FIG. 28 is a side elevational view of the fin-strip receiving conveyor;

FIG. 29 is a plan view of the fin-strip receiving conveyor;

FIG. 30 is a right-hand end view of what is shown in FIG. 29;

FIG. 31 is an exploded, much-enlarged diagrammatic perspective of themetal-stock trimmer;

FIG. 32 is a diagrammatic perspective view of the units involved in thelinear-travel control-element;

FIG. 33 is a perspective view of a limit switch, several of which areincorporated into the apparatus;

FIG. 34 is a diagrammatic view of the parts which guide the metal-stockthrough and from the aperture-protuberant forming elements and arrestaction if fin-strip jams;

FIG. 35 is a diagrammatic, plan view of the fin-strip advancing element;

FIG. 36 is a diagrammatic view of the funnel-shaped guide for directingthe emerging fin-strip from the cutoff onto the fin-strip advancingelement;

FIG. 37 is a much-enlarged, cross-sectional view of the finstripdischarging-element taken on the plane of the line 37- 37 ofFIG. 24; and

FIG. 38 is a perspective view of the part of the fin-stripdischarging-element that effects the retraction of the rails onto whicheach fin-strip is supported pending its discharge onto thereceiving-conveyor.

The type of product formulated on this apparatus, and its general mannerof use, are indicated in FIGS. 3, 4 and 5.

FIGS. 3 and 4 are perspective views of two of many forms of fin-stripsthat are producible of this nature. The apertures, in each case, are ofelongated contour bounded by pairs of flanges disposed transverse to theplane of the strip. As these figures show, there is a preference forstaggering adjacent rows of these apertures. Also, as here shown, thesespecimens have different forms of protuberances. In FIG. 3 these are inthe nature of small, circular embossments. In FIG. 4 the protuberancesare of a form commonly designated louvers. Whatever the shape, theseprotuberances, preferably, are positioned between the adjacentapertures.

Although the fin-strip specimens of FIG. 3 and 4 are tworow" type, itshould be understood that fin-strips of this character can be produced,with almost any reasonable multiple rows, in an apparatus as hereinillustrated and described.

A fin-strip forming apparatus, embodying the foregoing concept,comprises, a supporting framework A whereon is arranged sequentially acoil-holding element B, a peripheral hemmer element C, a fin-stockfeeding element D, a lineartravel-control element E, an aperture andprotuberant-forming element F, a fin-strip cutoff element G, a fin-stripadvancing element H, a finished fin-strip discharging element 1 and afin-strip receiving conveyor J, all operated by five motor-units M1, M2,M3, M4 and M5, subject to automatic and/or manual regulation through themedium of a circuit-control panel K.

The intrinsic and basic core-feature of this apparatus is theaperture-protuberant forming element F and the directly associatedcutoff element C. It is to this basic core-feature that a thinmetal-stock is directed by the controlled, sequential functioning of theelements B, C, D and E, arranged in advance (i.e., to the right of theforming and cutoff elements) and it is from this basic core-feature thatthe finished fin-strips are directed by the elements H and I, arrangedforwardly (that is to the left of the forming and cutoff elements) fororderly stacking on the conveyor J. Since these elements F and G thuslyconstitute the intrinsic basic core-feature of this development, thedetails of that dual structure and its operation will be set forthfirst. The other noted fore-elements B, C, D and E and aft-elements H, land J will be described later, in

that sequence.

The aperture-protuberant forming element F, as variously illustrated ondrawing sheets four through seven, comprises a pair of cylinders 21 and22, the latter being keyed to a shaft 23 (FIG. 16)journaled on anelevated platform 20 (FIG. 12) substantially medially of the overalllength of the framework A. The cylinder 22 is driven by a laterdescribed gear-pulley-train 25, subject to an air clutch 30 (FIGS. 13and 32).

The cylinder 21 is formed with a plurality of circumferential series ofaxially spaced, elongated apertures 32, with adjacent seriescircumferentially staggered, as shown in FIG. 18. In between theseopenings 32 are groups of pins 33 (FIG. 17). Within this cylinder 21 arearranged axially spaced, circumferential groups of punches 26 radiallyreciprocable in the openings 32 during the rotation of the cylinder 21.The cylinder 22 is formed with a plurality of circumferential matchingseries of recesses 32a. In between these recesses 32a are arrangedgroups of depressions 34 (FIG. 17) matching the series of pins 33 on thecylinder 21.

The reciprocation of the punches 26 is effected by a comparable seriesof axially spaced concentric cam devices 27, during the relativerotation of the cylinders 21 and 22 (FIG. 16). These cam devices 27 arein the nature of rings, each of which embraces a lobe 36 reciprocable inthe plane of the radii of the two cylinders 21 and 22 (FIG. 16).

The form and suspension of a lobe 36 is shown in FIGS. 16A and 17. Eachis secured to the threaded end of a bolt 42 within the cam device 27 byside projections 36a (FIGS. 16A and 19A) with the offset portion of thelobe seated in a slot 41 of the respective punch. The bolt 42 isembraced in a sleeve 43 with a compression spring 45 interposed betweenthe head 44 of the bolt 42 and the sleeve 43 intermediate the shaft 23and the cam ring 27.

It is the recurrent rotation of these cylinders 21 and 22 that causethese punches 26 to penetrate the metal-stock and form the flangedopenings 32 and cause the pins 33 and the depressions 34 to form theintermediate protuberances all as shown in FIGS. 3 and 4. Moreover, itis the penetration of these punches into the metal-stock that accountsfor the draft of that metal-stock from the aforesaid advance elementsand simultaneously directing the potential fin-strip to the cutoffelement G, for discharge to the tin-strip advancing element H.

A metal-stock holddown artifice 28 is located adjacently in advance ofthe cylinders 21 and 22 (FIGS. 1, 12 and 14). This involves a plate 46adjustably fixed on the platform 20. The plate 46 is so positioned thatthe under face thereof is just enough above the face of the platform topermit the desired travel of the metal-stock in its approach to thecylinder 21 and 22. Attached to this plate 46 is a tube 47 registeringwith a central hole in the plate 46. This tube 47 is connected to aregulated source of compressed air. The air discharged through the tube47 so impacts the metal-stock as to hold it firmly against the face ofthat part of the platform 20 as the stock approaches thefin-strip-forming cylinders 21 and 22.

As most clearly shown in FIG. 14 this plate 46 is secured in place onthe platform 20 by a series of spaced bolts 48 set in plate slots. Thesepermit a close adjustment of the plate 46 with respect to the opposedface of the platform 20 as may be required by the nature and theapproach of the metal-stock to the cylinders 21 and 22.

A metal-stock guide 29 (FIGS. 14 and 34) is arranged adjustably on thisplatform 20, in advance of the cylinders 21 and 22. The edge opposed tothe cylinders is tapered so as to permit adjustment as closely asrequired to the periphery of the cylinder 21, as conditions seem toindicate. Directly forward of the cylinders 21 and 22 is positioned atin-strip jamming switch 37. (FIG. 34)

The fin-strip cutoff element G is illustrated variously in FIGS. 12-1414A,l6 and 20-23 on sheets four and eight. Such G element involves apair of knife-edge members 58 and 59 respectively fixed and rotativelymounted on a pair of opposed standards 60 anchored to the framework Aforwardly of the aperture-protuberant forming element F.

The knife-edge member 58 is recessed in a bar 61, attached to standards60, transversely spanning the platform 20 above the path of thefin-strips discharged from the cylinders 21, 22. The exposed face of themember 58 is obtus'ely tapered to form the cutting edge medially of thelength of the member 58. The standards 60 are secured at their oppositeends to lateral parts of the framework A by suitable bolts not shown.Such a member 58 is suspended in the bar 61 by a series of bolts 58',embraced in a slot in the under face of the bar 61.

The knife-edge member 59 is recessed axially in a supplemental cylinder62 journaled on the framework A directly below the path of the advancingfin-strip. That cylinder 62 is journaled, by ball-bearings 64 (FIG. 21)on a shaft 63 for rotation in the direction of the arrow shown in FIG.23. The knifeedge member 59, with a less obtuse cutting edge, isembraced by a U-shaped part 65 recessed radially in the cylinder 62 anda slotted plate 66 bonded along the inner face of the cylinder 62 (FIG.23). This knife-edge member 59 is adjustably supported in the U-part 65,by a series of bolts 67, to ensure the exposed edge being in lightcontact with the knife-edge of the member 58, as will be seen from FIGS.23. The main portion of the face of the cylinder 62 is formed betweenaxially spaced ribs 68 substantially equal to the radial dimension ofthe transverse upset aperture tlanges and protuberances of thefinstrips. (See FIGS. 3 and 4) The bar 61 is suspended on the respectivestandards 60 by pairs of opposed bolts 53 (FIGS. 20 and 22). Thesepermit a needed transverse adjustment of the bar 61 to ensure the crownof the knife-edge member 58 being precisely in vertical alignment withthe axis of the shaft 63 and the knife-edge of the member 59.

The shaft 63, as most clearly shown in FIGS. 20 and 21, is arranged onthe standards 60, and has associated therewith a brake mechanism 69.This standard-shaft arrangement involves a key 54 set in the end of theshaft 63 and a cup-shaped disk 56 embracing the end of the shaft 63 andsecured in place by screws 57. The key 54 secures the shaft 63 againstany rotative action. However, an adjustment of the opposed bolts 53permits a slight shift of the bar 6] sufficient to ensure the requiredcontact of the cutting edges of the members 58 and 59, to make certainthat the successively produced fin-strips are absolutely of the samelength.

The brake mechanism 69 (FIGS. 20,22) involves a comparatively narrow,quadrant-shaped part, lined with a strip of friction material 51. It ishinged to one of the standards 60 for activation by an air-cylinder 52,as will be explained later.

It should be observed here that, as clearly indicated in these FIGS. 12,13, and 14, the aperture-protuberant forming element F and the fin-stripcutoff element G are synchronized in their functioning through thehereinbefore-noted gear-pulleytrain 25.

This gear-pulley train 25, driven by the motor M2 (FIGS. 12, 13 and 14)through the medium of a belt 122, pulleys 122A and 1228, and thepresently explained group of gears, shown in FIGS. 14 and 14A,synchronizes the above-explained functioning of the fin-strip formingcylinders 21 and 22 and the cutoff cylinder 62. The pulleys 122A and122B are keyed, respectively, to ajack-shaft 122C (middle of FIG. 12)and the shaft 24 of the fin-strip forming cylinder 22 (FIGS. 15, 16,17). The belt 122 spans the pulleys 122A and 122B respectively keyed tothe jack-shaft 122C and the shaft 24 of the finstrip forming cylinder22. This jack-shaft 122C is driven by a belt from a pulley, not hereshown, keyed to the rear end of that shaft driven by the motor M2.

This group of gears, which effect the synchronized functioning of theabove-noted cylinders 22 and 62, is clearly shown in FIGS. 14 and 14A.These involve a pinion 123, first pair of gears 124 and 127, a pinion125, a second pair of gears 128 and 129 and a gear 130. As most clearlyshown in FIG. 24A the first pair of gears 124 and 127 and the secondpair of gears 128 and 129, with the interposed pinion 125, are driven bythe pinion 123 to ensure the aforesaid synchronized functioning of thecylinders 22 and 62.

As previously observed, all the'other-noted advance elements B, C, D andE and the forward elements H, I and J are structured and arranged tofacilitate the best possible functioning of these just-delineated basiccore-feature elements F and G. The form and functioning of theseabove-noted other elements now will be set forth in that order.

The coil-support element B, as herein shown (FIGS. 1, 6 and 7), is anopen rack with a base 70 mounting a pair of rails 71 supported on pairsof posts 72. This element B is ofa length to permit the positioning oftwo coils of metal-stock on these rails 71. However, FIG. 1 shows onlyone in-service coil of metal-stock. A supporting shaft 73 (FIG. 6),extending through the coil core-opening, is supported on a pairofjournal bearings 74 (FIG. 6), at the forward extremities of the rails71. When the apparatus is in continuous production of finstrips, asecond coil of metal-stock is set on the rails 71 further in advance ofthe in-service coil. This permits an operator to make an almost instantinsert of the lead end of the metalstock from the second coil to followthe trailing end of the metal-stock on the coil hereinshown on thesupport element B.

A removable air-brake 75 is fixed on the shaft 73 and connected to asource of compressed air (not shown) by a tube 76 (FIGS. 6 and 7).Normally the air-brake 75 is open to permit the free advance of themetal-stock as required by the continuing operation of the previouslydescribed aperture-protuberant forming element F and the associatedfin-strip cutoff element G. As will be explained presently any irregulardemand on the metal-stock rail will cause the air-brake to arrest anyfurther release of the metal-stock (See operation").

The metal-stock hemmer element C and the feeding element D are arrangedjuxtaposed on the top of a cabinet 77 integrated with the framework A(FIGS. 1, 6 and 7).

The nature of this hemmer element C is most clearly indicated in FIG.31. This comprises a pair of spaced parts 78 and 79 fixed in oppositiondirectly forward of the feeding element D. As this FIG. shows, theinterior of the opposed faces 80 and 81, of these parts 78 and 79 effecta 90 flange. Thereupon, contact of the advancing metal-stock with faces82 completes a 180 turnover of the very narrow lateral portions of themetal-stock as it approaches the feeding element D.

Contiguously in advance of this hemmer-element C is fixed a curved apron83 (FIG. 13) for directing the metal-stock to this hemmer element C.

The metal-stock feeding element D is illustrated in FIGS. 8-11. As thererevealed this element D comprises a pair of superimposed housing parts85 and 86 (FIG. 11) respectively journaling rollers 87 and 88. Theroller 87 has formed thereon a series of peripheral grooves 89 whichaccommodate the metal-stock flanges for various widths thereof. Therollers 87 and 88 are driven by gears 90 subject to the action of alater described air clutch 93.

The linear-travel control element E is a most imperative feature toensure a requisite movement of the metal-stock to the previouslyexplained core-feature combination of elements F and G. The structure ofthis linear-travel control element is illustrated in FIGS. 1, 6 and 7.The arrangement of parts and their functioning is diagrammaticallyindicated in FIG. 32. As shown in these several figures this element isin the nature of a rack 91 comprising a welded pair of side panels 92and forming an elongated open-top pit 94. Through this pit 94 themetal-stock variously loops in its advance from the feeding element D tothe aperture-protuberant forming element F. On and in this rack 91 arefixed a potentiometer 95, in circuit with upperand lower-limit switches96 and 97, and a conventional photoelectric light-system 98.

Each of the two limit switches 96 and 97, as shown in FIG. 33 comprisesan arm 101 secured to a rod 102 journaled on a housing 103 wherein isarranged a conventional microswitch (not shown). Such switches aresubject to closing or opening by the opposite turning of the respectiverod 102, as effected by the action of the metal-stock, traversing thepit 94, contacting the arm 101, as later will be explained more fully.

The photoelectric light-system 97 involves a conventional opposedarrangement of an electric-eye component 104 and a photocell 105. Thefunctioning of this linear-travel-control element E will be describedlater herein.

Adjacently above the ends of this rack 91 are oppositely arranged thearcuate-shaped aprons 99 and (FIG. 7 These are fixedly positioned on theframework A juxtaposed, respectively, to the exit of the metal-stockfeeding-element D and the entrance to the aperture-protuberant formingelement F.

Such is the general nature of these advance elements B, C, D and E, thatfeed the metal-stock to these just-described basic core-elements F andG. Attention now will be focused on the forward" elements H, I and Jthat receive, advance and stack the pre-formed fin-strips subject tolater use.

The fin-strip advancing-element I-I. As most clearly shown in FIGS. 24and 25 the framework A mounts a platform 106 in planar alignment withthe platform 20 (FIG. 12). Below this platform 106 are arranged therespective aligned pairs of rails 107 and 108 (FIGS. 24 and 26) alongwhich travel the finished fin-strips discharged from thehereinbefore-described fin-strip cutoff element G. A highly-acceleratedmovement of these fin-strips along these pairs of rails 107 and 108, fordischarge onto the conveyor J, is effected by sets of brushes 109 and110, journaled on standards 111 and 112 (FIG. 25), driven by belts 113and 114 (from the motor M3) subject to a speedcontrol device 138.

Intermediate the cutoff element G and these rails 107 is arranged ashort, flat, funnel-shaped fin-strip guide 107A (FIG. 36). This servesto ensure the advancing end of the accelerated fin'strip which will beguided properly onto the rails 107.

The brushes 109 and are driven by a pair of belts 113 and 114. The belt113 spans a pulley 136, keyed to the forward end of the shaft 133 of themotor M3, and a pulley 139, keyed to the forward end of the shaft 135journaled on-the standard 112. It is on this shaft 135 that the pair ofbrushes 110 are axially fixed (FIG. 24). The belt 114 spans a pulley 134keyed to the rear end of the shaft 135, and a pulley 134A keyed to therear end of a shaft 137 journaled on the standard 111. It is to thisshaft 137 that the pair of brushes 109 are fixed.

This speed-control device 138 involves a shaft 140 spanning a pair ofposts 141 and supporting a pair of parts 142. A threaded rod 143, fixedat one end to a hand-wheel 144, is

by a tubular frame 1 15, and with the underset pair of rails 108 mountedfor recurring transverse retraction by pairs of opposed solenoids 117 asinstrumented by the approach of each fin-strip to a sensing instrument118. These pairs of solenoids 117 are arranged in transverse oppositionintermediate the opposite ends of the platform 106 (FIGS. 24, 25).

The sensing instrument 118 is located on the under face of thisreinforced platform 106 between the most forward of the pair ofsolenoids 117 and the extremity of that section of the platform 106.

The details of an opposed pair of solenoids 117 and the sensinginstrument 118 are shown in FIGS. 37 and 38. The action of thesesolenoids is biased by springs 119 to normally position the rails 108 inalignment with the rails 107 of the just-described fin-stripadvancing-element H.

This sensing instrument 118 comprises a plate 120 and anelectrical-field creating core 121 suspended in an arcuate cavity 121'.This creates a constant electronic field subject to invasion by eachadvancing fin-strip to activate the two pairs of solenoids 117 toretract the rails 108, against the springs 119, to drop each suchfin-strip onto the receiving conveyor J.

The fin-strip receiving conveyor J is shown in FIGS. 1, 6, 7, 28, 29 and30. This comprises a leg-supported platform 146 with the rollers 147 and148 spanned by a belt 149 which is driven by the motor M4, as presentlywill be noted. A pair of conventional belt-tensioning means 150 areassociated with the roller 147.

The circuit-control element K (FIGS. 1 and 7) is a conventional type ofunit with a sloping front-panel mounting a series of buttons 155. Theseare for manual activation of various switches controlling the variouscircuits leading to the several motors M1, M2, M3, M4 and M and otheroperation-controlling parts as hereinbefore designated. These buttons155 are formed of variously colored, translucent material. When any oneof these buttons is depressed it becomes illuminated to indicate thatthe circuit to a certain part of the apparatus is ready for normalfunctioning.

The previously noted five primary motors M1, M2, M3, M4 and M5,respectively, account for the operation of the metalstock feedingelement C, the aperture-protuberant forming element F and coordinatedfin-strip cutoff element G, the finstrip advancing-element H, thefin-strip receiving element J, and an air-compression unit for theentire apparatus.

The M1 motor, as shown in FIGS. 8 and 9, is set within the cabinet 77with a belt 38 connecting the motor pulley 39 with a pulley 40 which inturn is connected to drive the roller 88. How this M 1 motor effects thefeeding of this metal-stock will be explained presently.

The motor M2, which coordinates the functioning of the elements F and G,is set within that portion of the framework A which mounts theaperture-protuberant and cutoff elements F and G. It is connected todrive the hereinbefore-noted gearpulley-train 25.

As indicated in FIG. 32 the motor M1, for the metal-stock feedingelement D, and the motor M2, for the metal-stock aperture-protuberantforming element F, have associated with them the respective disc-o-type"air-clutches 93 and 30. These clutches come into action, respectively,to arrest the draft on the metal-stock when the switch 96 is activatedor arrest the draft of the stock by the rollers 87-88 when themetalstock comes into contact with the switch 97. This, and thefunctioning of these limit switches 96 and 97 will be delineated in thesubsequent "operation" section of this specification.

The motor M3, as shown in FIG. 25, is mounted on the cabinet 116 whichforms a portion of the framework A of FIG. 1. This motor is connected todrive brushes 109 and 1 10 through the medium of belts 1 l3 and 114(FIGS. 24, 25).

The motor M4 is associated with the fin-strip receiving conveyor J(FIGS. 28 and 29) and is driven at a much retarded speed, compared withthe motors for the previously described elements D, F, H and I. Thispermits an overlapped stacking of the fin-strips as they are dischargedby the element I onto the conveyor J. (See FIGS. 1 and 2) This motor M4is mounted on a ledge fixed at the rear of the conveyor element .1,(FIG. 29) intermediate the floor and the platform 146. A belt 149 spansa sheeve 151 on the motor M4 and a sheeve 152 keyed to the rear roller147.

- The motor M5 also is set in that portion of the framework A whichmounts the aperture-protuberant and cutoff elements F and G. (FIG. 12)This motor operates a compressor (not shown) to supply pressure to theherein-noted air valves.

The operation of this apparatus, for transforming metalstock intoaperture-protuberant fin-strips, involves the followmg:

It is pertinent to reiterate a prior assertion as to these associatedelements F and G which are the intrinsic and basic core-feature of thisapparatus. It is upon the coordinated action of these parts that allother elements of this apparatus inherently are dependent. Thus, theoperators first and evercontinuing concern has to do with theappropriate functioning of the cylinders 21, 22 and 62 and theirassociated parts which ultimately account for the production of thedesired fin-strips.

The first action of the operator is to punch certain of these buttons onthe circuit control element K, to ascertain that the five motors and theassociated major units all are in circuit readiness, as will beindicated by the illumination of the respective buttons 155. With suchassurance the button to the air-clutch 30 and 93 is depressed. Thereuponthe apparatus begins to function to produce fin-strips at a highacceleration.

Taken in sequence, the M1 motor, for the metal-stock feeding element D,begins to draw the metal-stock from the coil on the support element B.Thereupon the metal-stock advances through the hemming element C. Asthis metal-stock moves along the faces 80 of the blocks 78 and 79 (FIG.31), one or both lateral portions contact the faces 81 whereupon narrowmarginal portions are disposed transversely to the plane of the stock.As the advance of the stock continues between the faces of the parts 82such marginal portions of the metal-stock are pressed down firmlyagainst the face of the stock. (FIG. 3 1

With its emergence from the metal-stock feeding element D this thuslyhemmed portion loops downwardly into the pit 94 of thelinear-travel-control element E and upwardly therefrom to theaperture-protuberant forming element F. (FIGS. 1 and 2) However, theelement D feeding this hemmed stock, by the motor M1 and the coordinatedpull thereon by the cylinders 21 and 22 of the element F, is subject, attimes to considerable alteration as it moves through thelinear-travel-control ele ment E. (See FIGS. 1 and 32) So long as themetal-stock, moving through the pit 94, is below the beam of thephotoelectric-light system 98, and remains out of contact with eitherlimit switches 96 and 97, the metal-stock continues its advance throughthe pit 94. This movement is at a predetermined rate to meet the demandsof the cylinders 21 and 22 of the element F as they continue convertingthe metal-stock into potential fin-strips. However, in the event theloop of metal-stock in the pit 94 is such that it is so high or low asto activate the one or the other limit switches 96 or 97, respectively,there will be an automatic alteration of the advance of the metal-stockthrough the pit 94. For example: if the metal-stock should rise to apoint of contacting the arm 101 (FIG. 33) of the upper limit switch 96(FIG. 32) the air clutch 30 would be deactivated and the air-cylinder 52activated. The movement of the cylinders 21, 22 and 61 would bearrested. However, the rollers 87 and 88 of the element D would continuefeeding the metal-stock into the pit 94, until the stock becomes loweredto the point of contacting the arm 101 and the lower limit switch 97.This would result in the deactivation of the air-clutch 93, therebycompletely arresting the functioning of the apparatus. It then becomesnecessary for the operator to depress the button on the circuit controlelement K to re-activate the air clutches and 93 and release the aircylinder 52. The apparatus thereupon will resume its normal functioning.

Otherwise, so long as the metal-stock intercepts the light beam of thephotoelectric-light system 98 there is a more-orless constant advance ofthe metal-stock from the stock-feeding element D to the fin-formingcylinders 21 and 22 of the element F. However, should the loop ofmetal-stock in the pit 94, rise above the beam of thephotoelectric-light system 98, the potentiometer 95 would beinstrumented to effect a slight increase in the speed of the motor Ml.As soon as that effects an increased advance of the metal-stock, to thepoint of again intercepting the aforesaid light-beam, the potentiometer95 would be instrumented to return the motor M1 to the intended speed toaccommodate the advance of the metal-stock to the demand of thecylinders 21 and 22 of the element F.

Normally, the hemmed metal-stock advances out of the pit 94 up over theapron 100 and into the holddown artifice 28 for feeding to the basiccore-feature forming-element F. A predetermined air-pressure through theair-tube 47 serves to hold the metal-stock firmly against the face ofthe platform 20 (FIG. 12) as the metal-stock is drawn between thecylinders 21 and 22 of this element F operating at speeds between 136and 375 revolutions per minute. The successive activation of the annularseries of punches 26, in the cylinder 21, by the lobes 36 of therespective cam devices 27, effects the forming of the continuingsuccession of flanged apertures 32 in the metal-stock. Concurrently, theseries of pins 33 and the depressions 34 (FIG. 17) form the tuberancesin between these apertures. Meanwhile these cylinders 21 and 22 arecausing the continued advance of the potential fin-strip to thecutoffelement G. (FIGS. 12 and 14) Due note should be taken of how thesepunches 26 approach and recede from the recurring forming of the flangedopenings 32 in the specimen fin-strips of FIGS. 3 and 4. It will be mostobvious from FIG. 19A that as these two cylinders 21 and 22 rotate theV-tapered end of each punch 26 approaches a recess 32a of the cylinder22. These initiate the forming of depressions in the rapidly-advancingfin stock. As each punch acquires its full depression into a recess 32athe formation of a flanged aperture is completed. The continued movementof the cylinders effects the retraction of the punch 26 that has justcompleted the formation of the respective flanged openfhe succession ofsuch formed fin-strips are precisely of the same length by reason of thegear mechanism between the cylinders 21 and 22, as shown in FIG. 14A.The length, for any series of fin-strips, can be altered merely bychanging the gear 128.

In the event this forward movement of the potential fin-strip shouldfail its intended advance to the cutoff element G, the fin-strip wouldtend to bunch-up between these two elements F and G. The resultingcontact with the arm 101 of the switch (FIGS. 34 and 35) woulddeactivate the clutch 30 and arrest functioning of the cylinders 21 and22. Meanwhile, the metal-stock would be lowered in the pit 94 to thepoint of activating the switch 97 and arrest the metal-stock feedingelement D. Such a fault would emanate from either of several sources.One might be failure in the functioning of the cutoff element G. Anothermight be some failure in the functioning of the brushes 109 and 110. Itmight be the result of an aircylinder failure or the failure of thesensing device of the finstrip discharging element J.

Otherwise, the synchronized cylinder 62 of this cutoff element Gcontinues the advance of this forming fin-strip emerging from theforming element F. Each revolution of the cylinder 62 brings the cuttingedge of the member 59 into vertical alignment with the knife-edge of themember 58 (FIGS.

19L 20-23). Thereupon a predetennined length of the emerging fin-stripis severed for discharge onto the fin-strip advancing element H (FIGS.24,25 and 35).

As clearly will be evident from the juxtaposition of the cuf off elementG and the fin-strip advancing element H, the forward portion of theforming fin-strip, emerging from the element G, is traversing the rails107 of this advancing element H. Thus, the forward pair of brushes109directly adjacent the cutoff element Gare in contact with theadvancing end of this forming fin-strip (FIGS. 25 and 35). However, atthe instant the fin-strip is severed by the knife-edges of 58 and 50,the two pairs of brushes 109 and 110, shoot the severed section offin-strip forwardly onto the tracks 108 of the fin-strip dischargingelement I. (FIGS. 24-25) As the advancing end of each finished fin-stripapproaches the sensing instrument 1 18 it is activated to open thecircuit to the pairs of air-cylinders 117 to permit the springs 119 toretract the opposed rails 108. Thereupon the finished fin-strip dropsonto the belt 140 of the receiving conveyor J. Such actuation of thesolenoids 117 is due to the advance of forward edge of the fin-stripinto the field created in the cavity by the energization of the core121.

As hereinbefore noted, and as previously explained, and clearlyindicated in FIGS. 1 and 2, the movement of this conveyor belt 149 isgreatly retarded, compared with the functioning speed of the cylinders21 and 22. Thus, as illustl'ated in FIG. 1, these successivelydischarged fin-strips stack up on the conveyor belt with only slightlyless than a complete overlap of each successive fin-strip dropped ontothe conveyor belt 149.

Variations and modifications in the details of structure and arrangementof the parts may be resorted to within the spirit and coverage of theappended claims.

We claim:

1. An apparatus for the transformation of metal-stock into individual,apertured, planar fin-strips for stacked use in structuring tubularheat-exchanger core-units, comprising a. a supporting framework,

b. a pair of cylinders journaled one above the other on the frameworkfor passage of metal-stock between the peripheries of the cylinders,

c. one cylinder having a plurality of circumferentially spaced, radiallydisposed, elongated openings arranged uniformly axially of the cylinder,

d. the openings of one radially disposed series being axially staggeredwith respect to the openings of the next adjacent series,

e. the other cylinder having a matching series of recesses formedtherein,

f. an annual series of punches reciprocally embraced in the openings inthe one cylinder, each punch having a slot adjacently the inner endthereof,

g. a series of flanged annuluses positioned between the respectiveseries of punches with the flange on each extending into the slot of theadjacent punch,

h. a lobe associated with each annulus in the plane thereof extendingradially toward the other cylinder for successively activating therespective series of punches during the rotation of the cylinders,

i. a bar fixed directly forward and parallel with the pair of cylindersthe exposed face of which is tapered to form a knife-edge disposedlongitudinally of the bar,

j. a supplemental cylinder journaled on an axis aligned with the ridgeon the bar,

k. a second bar recessed inwardly of the periphery of the supplementalcylinder and having its exposed face tapered to form a knife-edgedisposed longitudinally of the second bar in vertical alignment with thefirst bar knife-edge, and

. a motor-driven gear-pulley-train on the framework for synchronizingthe rotation of the pair of cylinders and the supplemental cylinder tosever the emerging fin-strip into predetermined uniform lengths.

2. An apparatus as set forth in claim 1 wherein each lobe is suspendedon a bolt with an interposed spring that normally retracts therespective lobe when not in metal-stock aperturing position.

3. An apparatus as set forth in claim 1 wherein one of the gears of thegear-pulley-train is replaceable by a gear of a different pitch to alterthe rotation speed of the cylinders to vary the uniform length of thefin-strips.

4. An apparatus as set forth in claim 1 wherein a pair of finstripadvancing rails and associated motor-driven brushes are locatedforwardly of the supplemental cylinder and bar for accelerating theadvance of the several fin-strips for stacking subject to use forstructuring core-units.

5. An apparatus as set forth in claim 4 wherein another pair of railsare aligned with the first pair of rails for receiving the tin-stripsadvanced by the motor-driven brushes, the second pair of rails beingspring biased for normal alignment with the first pair of rails, and asensing instrument positioned forwardly between the second pair of railsactivated by each advancing fin-strip to separate the rails tosuccessively discharge the fin-strips for stacking on an underplacedsupport.

6. An apparatus for effecting the transformation of thin metal-stockinto predetermined length, planar fin-strips with elongated flangedapertures for use in structuring tubular heat exchanger, comprising a. asupporting framework for mounting a supply of metalstock,

b. a pair of opposed cylinders journaled on the framework for thepassage of the metal-stock between the peripheries of the cylinders,

c. each of the cylinders having a plurality of radial series of axiallyspaced registering openings formed therein and spaced uniformly aroundand along the cylinders,

an equal plurality of reciprocable punches embraced in the openingsofone of the cylinders,

e. cam means operatively connected in said one cylinder for successivelyactivating the punches during the continuous and uninterrupted rotationof the cylinders to form apertures in the metal-stock advancing betweenthe cylinders,

f. other means operatively connected with the cylinders for advancingthe metal-stock to the cylinders,

g. a pair of members operatively connected with the cylinders and beinglocated in the path of the stock discharge from the cylinders and beingoperable synchronically with the cylinders to sever the advancing stockinto uniform-length fin-strips,

h. motor means operatively connected in the apparatus for causing thesynchronized rotation of the cylinders, actuation of the cam means andthe stock-severing members,

i. a guide-means arranged on the framework forwardly of the fin-stripsevering members for receiving the severed fin-strips,

j. other means operatively associated with the guide means foraccelerating the advance of each severed fin-strip and successivelydischarging them,

k. and a fin-strip stacking element operatively associated with saidother means for receiving the severed fin-strips.

7. An apparatus as set forth in claim 6, wherein the other means foraccelerating the advance of the cut-off fin-strips is a motor-drivenbrush positioned to contact the under face of each fin-strip dischargedonto the guide-means.

8. An apparatus as set forth in claim 6, wherein the stacking element isa slow-moving conveyor belt disposed and arranged for movementtransversely of the supporting framework.

9. An apparatus as set forth in claim 6, including a componentoperatively disposed aligned forwardly with the finstrip receivingguide-means and the associated other means, for temporarily supportingeach fin-strip successively advanced by the associated other means, andan electronic sensing instrument juxtaposed to the component, andsubject to activation by the approach of each fin-strip, for dischargeof each fin-strip onto the stacking element.

10. An apparatus as set forth in claim 9, wherein the component is inthe form of a pair of spaced rails aligned with the fin-strip advancingmeans and is disposed above the stacking element and is transverselyshiftable into and out of disposi tion for receiving fin-strips from thefin-strip advancing means and including spring-biased solenoidsconnected to the rails to normally bias the rails into position toreceive the fin-strips successively advanced by the associated othermeans, and including a sensing device in the form of an electric-fieldcreating-core operatively connected to the rails and activated by theapproach of each fin-strip to effect the electric field to causeseparation of the rails to drop each fin-strip onto the stackingelement.

11. An apparatus as set forth in claim 6, including a motordrivenmetal-stock feeding-element operatively positioned in advance of thecylinders, and means interposed between the metal-stock feeding-elementand the cylinders for automatically controlling the linear advance ofthe metal-stock to the cylinders.

12. An apparatus as set forth in claim 6, wherein the supportingframework, intermediate the metal-stock feeding-element and the apertureforming element, defines an elongated pit for receiving a curved extentof the metal-stock between these means and cylinders, and upper andlower sensing devices operatively connected in the apparatus andarranged in the pit in the path of the advancing metal stock for sensingthe extent of the curve and correspondingly automatically regulating anyfluctuating travel of the metalstock through the pit.

13. An apparatus as set forth in claim 12, wherein the sensing devicesare switches disposed above and below the curve and are fixed on theframework-defined pit whereby the advancing metal-stock contacting oneof the switches will temporarily accelerate the feeding of themetal-stock into the pit, and the metal-stock contacting the otherswitch will temporarily accelerate the draft of the metal-stock from thepit.

14. An apparatus as set forth in claim 12, including aphotoelectric-light system arranged horizontally in the elongated pitand being operatively connected to the linear advance means to normallymaintain the curve of metal-stock free of contact with the sensingdevices.

15. An apparatus as set forth in claim 12, including an airclutchoperatively connected with the metal-stock advancing means, and anair-clutch operatively connected with the forming cylinders, wherebycontact of the metal-stock with the upper sensing device will deactivatethe air-clutch for the cylinders to permit an increased advance of themetal-stock into the pit, and whereby contact of the metal-stock withthe lower sensing device will deactivate the air-clutch for the feedingrollers to permit an increased draft of the metal-stock from the pit bythe forming cylinders.

16, An apparatus as set forth in claim 12, including a potentiometeroperatively connected to the photoelectric system whereby when the drafton the metal-stock rises above the beam of the photo-electric-lightsystem the potentiometer will slightly accelerate the drive of the motorfor the metal-stock advancing means to increase the curve thereof in thepit, and when the curve of the metal-stock again intercepts the beamfrom the photo-electric-light system the potentiometer will be activatedto decrease the speed of the motor to the metalstock advancing means torestore the normal advance of the metal-stock to the forming cylinders.

17. An apparatus as set forth in claim 6, wherein said pair of membersare rotatable cutting cylinders, and including a gear train for theoperative connection of said cutting cylinders with said othercylinders, and one of the gears of said gear train being replaceable bya gear of different size to alter the rotation speed of said cuttingcylinders to vary the length of the cut fin-strips.

1. An apparatus for the transformation of metal-stock into individual,apertured, planar fin-strips for stacked use in structuring tubularheat-exchanger core-units, comprising a. a supporting framework, b. apair of cylinders journaled one above the other on the framework forpassage of metal-stock between the peripheries of the cylinders, c. onecylinder having a plurality of circumferentially spaced, radiallydisposed, elongated openings arranged uniformly axially of the cylinder,d. the openings of one radially disposed series being axially staggeredwith respect to the openings of the next adjacent series, e. the othercylinder having a matching series of recesses formed therein, f. anannual series of punches reciprocally embraced in the openings in theone cylinder, each punch having a slot adjacently the inner end thereof,g. a series of flanged annuluses positioned between the respectiveseries of punches with the flange on each extending into the slot of theadjacent punch, h. a lobe associated with each annulus in the planethereof extending radially toward the other cylinder for successivelyactivating the respective series of punches during the rotation of thecylinders, i. a bar fixed directly forward and parallel with the pair ofcylinders the exposed face of which is tapered to form a knifeedgedisposed longitudinally of the bar, j. a supplemental cylinder journaledon an axis aligned with the ridge on the bar, k. a second bar recessedinwardly of the periphery of the supplemental cylinder and having itsexposed face tapered to form a knife-edge disposed longitudinally of thesecond bar in vertical alignment with the first bar knife-edge, and
 1. amotor-driven gear-pulley-train on the framework for synchronizing therotation of the pair of cylinders and the supplemental cylinder to severthe emerging fin-strip into predetermined uniform lengths.
 2. Anapparatus as set forth in claim 1 wherein each lobe is suspended on abolt with an interposed spring that normally retracts the respectivelobe when not in metal-stock aperturing position.
 3. An apparatus as setforth in claim 1 wherein one of the gears of the gear-pulley-train isreplaceable by a gear of a different pitch to alter the rotation speedof the cylinders to vary the uniform length of the fin-strips.
 4. Anapparatus as set forth in claim 1 wherein a pair of fin-strIp advancingrails and associated motor-driven brushes are located forwardly of thesupplemental cylinder and bar for accelerating the advance of theseveral fin-strips for stacking subject to use for structuringcore-units.
 5. An apparatus as set forth in claim 4 wherein another pairof rails are aligned with the first pair of rails for receiving thefin-strips advanced by the motor-driven brushes, the second pair ofrails being spring biased for normal alignment with the first pair ofrails, and a sensing instrument positioned forwardly between the secondpair of rails activated by each advancing fin-strip to separate therails to successively discharge the fin-strips for stacking on anunderplaced support.
 6. An apparatus for effecting the transformation ofthin metal-stock into predetermined length, planar fin-strips withelongated flanged apertures for use in structuring tubular heatexchanger, comprising a. a supporting framework for mounting a supply ofmetal-stock, b. a pair of opposed cylinders journaled on the frameworkfor the passage of the metal-stock between the peripheries of thecylinders, c. each of the cylinders having a plurality of radial seriesof axially spaced registering openings formed therein and spaceduniformly around and along the cylinders, d. an equal plurality ofreciprocable punches embraced in the openings of one of the cylinders,e. cam means operatively connected in said one cylinder for successivelyactivating the punches during the continuous and uninterrupted rotationof the cylinders to form apertures in the metal-stock advancing betweenthe cylinders, f. other means operatively connected with the cylindersfor advancing the metal-stock to the cylinders, g. a pair of membersoperatively connected with the cylinders and being located in the pathof the stock discharge from the cylinders and being operablesynchronically with the cylinders to sever the advancing stock intouniform-length fin-strips, h. motor means operatively connected in theapparatus for causing the synchronized rotation of the cylinders,actuation of the cam means and the stock-severing members, i. aguide-means arranged on the framework forwardly of the fin-stripsevering members for receiving the severed fin-strips, j. other meansoperatively associated with the guide means for accelerating the advanceof each severed fin-strip and successively discharging them, k. and afin-strip stacking element operatively associated with said other meansfor receiving the severed fin-strips.
 7. An apparatus as set forth inclaim 6, wherein the other means for accelerating the advance of thecut-off fin-strips is a motor-driven brush positioned to contact theunder face of each fin-strip discharged onto the guide-means.
 8. Anapparatus as set forth in claim 6, wherein the stacking element is aslow-moving conveyor belt disposed and arranged for movementtransversely of the supporting framework.
 9. An apparatus as set forthin claim 6, including a component operatively disposed aligned forwardlywith the fin-strip receiving guide-means and the associated other means,for temporarily supporting each fin-strip successively advanced by theassociated other means, and an electronic sensing instrument juxtaposedto the component, and subject to activation by the approach of eachfin-strip, for discharge of each fin-strip onto the stacking element.10. An apparatus as set forth in claim 9, wherein the component is inthe form of a pair of spaced rails aligned with the fin-strip advancingmeans and is disposed above the stacking element and is transverselyshiftable into and out of disposition for receiving fin-strips from thefin-strip advancing means and including spring-biased solenoidsconnected to the rails to normally bias the rails into position toreceive the fin-strips successively advanced by the associated othermeans, and including a sensing device in the form of an electric-fieldcreating-core operativeLy connected to the rails and activated by theapproach of each fin-strip to effect the electric field to causeseparation of the rails to drop each fin-strip onto the stackingelement.
 11. An apparatus as set forth in claim 6, including amotor-driven metal-stock feeding-element operatively positioned inadvance of the cylinders, and means interposed between the metal-stockfeeding-element and the cylinders for automatically controlling thelinear advance of the metal-stock to the cylinders.
 12. An apparatus asset forth in claim 6, wherein the supporting framework, intermediate themetal-stock feeding-element and the aperture forming element, defines anelongated pit for receiving a curved extent of the metal-stock betweenthese means and cylinders, and upper and lower sensing devicesoperatively connected in the apparatus and arranged in the pit in thepath of the advancing metal stock for sensing the extent of the curveand correspondingly automatically regulating any fluctuating travel ofthe metal-stock through the pit.
 13. An apparatus as set forth in claim12, wherein the sensing devices are switches disposed above and belowthe curve and are fixed on the framework-defined pit whereby theadvancing metal-stock contacting one of the switches will temporarilyaccelerate the feeding of the metal-stock into the pit, and themetal-stock contacting the other switch will temporarily accelerate thedraft of the metal-stock from the pit.
 14. An apparatus as set forth inclaim 12, including a photo-electric-light system arranged horizontallyin the elongated pit and being operatively connected to the linearadvance means to normally maintain the curve of metal-stock free ofcontact with the sensing devices.
 15. An apparatus as set forth in claim12, including an air-clutch operatively connected with the metal-stockadvancing means, and an air-clutch operatively connected with theforming cylinders, whereby contact of the metal-stock with the uppersensing device will deactivate the air-clutch for the cylinders topermit an increased advance of the metal-stock into the pit, and wherebycontact of the metal-stock with the lower sensing device will deactivatethe air-clutch for the feeding rollers to permit an increased draft ofthe metal-stock from the pit by the forming cylinders.
 16. An apparatusas set forth in claim 12, including a potentiometer operativelyconnected to the photoelectric system whereby when the draft on themetal-stock rises above the beam of the photo-electric-light system thepotentiometer will slightly accelerate the drive of the motor for themetal-stock advancing means to increase the curve thereof in the pit,and when the curve of the metal-stock again intercepts the beam from thephoto-electric-light system the potentiometer will be activated todecrease the speed of the motor to the metal-stock advancing means torestore the normal advance of the metal-stock to the forming cylinders.17. An apparatus as set forth in claim 6, wherein said pair of membersare rotatable cutting cylinders, and including a gear train for theoperative connection of said cutting cylinders with said othercylinders, and one of the gears of said gear train being replaceable bya gear of different size to alter the rotation speed of said cuttingcylinders to vary the length of the cut fin-strips.